1. Technical Field
The present disclosure relates generally to an apparatus for permitting the introduction of a surgical instrument into a patient's body cavity in a laparoscopic or similar surgery. In particular, the disclosure relates to a telescoping cannula assembly configured for longitudinal extension and retraction to effect a length adjustment.
2. Background of Related Art
A relatively small incision is required for minimally invasive surgical procedures such as laparoscopic, arthroscopic, and endoscopic procedures as compared with conventional open procedures. Small incisions are preferred because they are inherently less traumatic to the body tissue and subject internal organs to a minimum of exposure to contaminants in the outside atmosphere. Thus, small incisions enable shorter hospital stays and faster recoveries with less pain and scarring than is common with the larger incisions required for conventional surgery.
Minimally invasive surgery is possible due in part to the availability of instruments designed specifically for this purpose. A cannula, for example, is an elongated tube that may be inserted through the small incision made in a body cavity wall of a patient to provide a working conduit between an internal body cavity adjacent an operative site and the environment exterior to the patient. The body cavity is often inflated with an insufflation gas such as carbon dioxide to separate the body cavity wall from vital organs and to provide some space where a distal end of the cannula can safely protrude into the patient below the body cavity wall.
The length of a cannula is generally selected to span a range of anatomies and consequently a portion of the cannula assembly which remains on the outside of the patient may extend above the body cavity wall to a greater extent than otherwise desired. The cannula assembly may need to extend into deeper regions of the body cavity, e.g., the abdominal cavity, to access remote underlying organs therein. Furthermore, because several instruments of various lengths might be required for a surgical procedure, an instrument may protrude above the cannula assembly to a greater extent than otherwise desired. Accordingly, a need exists for a cannula assembly which facilitates the introduction of surgical instruments to a surgical site, while allowing a longitudinal retraction or extension to effect an adjustment in length.